Garnet provenance signature on East and West Antarctic Ice-Sheet dynamics during the Plio-Pleistocene transition (IODP Expedition 374, Site U1523)

Antarctica is a unique natural laboratory for investigating interactions among climate change, ice-sheet dynamics, and subglacial geology, providing key insights into past climate variability and ongoing climate change. However, with nearly 98% of the continent covered by ice, direct access to geological and paleoenvironmental archives is limited. In this context, marine sedimentary records represent one of the few accessible natural records, allowing reconstruction of ice-sheet stability, sediment transport and climate variability. Here, we analyse heavy-mineral assemblages from samples recovered during IODP Expedition 374 at Site U1523, located on the margin of Iselin Bank in the Ross Sea. The site records continuous sediment accumulation derived from glacial erosion of both the West and East Antarctic Ice Sheets. Sediment supply to the site is also influenced by the Antarctic Slope Current (ASC), which plays an important role in sediment redistribution along the continental margin. Provenance analysis focuses on the micro-Raman characterization of garnet assemblages over 32 samples, spanning the last ~4 Myr. Garnet allows discrimination among metamorphic sources mostly associated with East Antarctica, magmatic sources linked to West Antarctica, and sources derived from the Transantarctic Mountains (TAM). Preliminary results highlight the potential of garnet-based provenance analysis to trace sediment sources and reconstruct Antarctic ice-sheet dynamics during the Plio-Pleistocene, while providing new constraints on Antarctic geology.